Background: Treatment of myocardial infarction with bone marrow-derived mesenchymal stem cells and recently also adipose-derived stem cells has shown promising results. In contrast to clinical trials and their use of autologous bone marrow-derived cells from the ischemic patient, the animal myocardial infarction models are often using young donors and young, often immune-compromised, recipient animals. Our objective was to compare bone marrow-derived mesenchymal stem cells with adipose-derived stem cells from an elderly ischemic patient in the treatment of myocardial infarction, using a fully grown non-immunecompromised rat model. Methods: Mesenchymal stem cells were isolated from adipose tissue and bone marrow and compared with respect to surface markers and proliferative capability. To compare the regenerative potential of the two stem cell populations, male Sprague-Dawley rats were randomised to receive intramyocardial injections of adipose-derived stem cells, bone marrow derived mesenchymal stem cells or phosphate-buffered saline one week following induction of myocardial infarction. Results: After four weeks, left ventricular ejection fraction was improved in the adipose-derived stem cell group and scar wall thickness was greater compared with the saline group. Adipose-derived as well as bone marrow-derived mesenchymal stem cells prevented left ventricular end diastolic dilatation. Neither of the cell groups displayed increased angiogenesis in the myocardium compared with the saline group.Conclusions: Adipose-derived stem cells from a human ischemic patient preserved cardiac function following myocardial infarction whereas this could not be demonstrated for bone marrow-derived mesenchymal stem cells, with only adipose-derived stem cells leading to an improvement in left ventricular ejection fraction. Neither of the stem cell types induced myocardial angiogenesis raising the question whether donor age and health have an effect on the efficacy of stem cells used in the treatment of myocardial infarction.